i whant to make an extension, which overrides the standard "newtab" page. There is a manifest key for that, called "chrome _url_overrides".
But when i use it, an error-message appears: "'chrome__url_overrides' is not allowed for specified extension ID."
Now i'm not sure if opera doesn't allow that in general, or if there is a way to "activate" it. In Chrome the same extension works just fine.